Organic light emitting diodes (OLEDs) can be used in a wide range of lightings, as well as high and low resolution display applications. The simplest OLED device contains an organic emission layer sandwiched between two electrodes that inject electrons and holes. The electrons and holes meet in the organic emission layer and produce light. Insertion of electron or hole transporting layers between the two electrodes renders the light production more efficient. See, e.g., Tang et al. (1987) Applied Physics Letters 51: 913–915, Burroughs et al. (1990) Nature 347: 539; Adachi et al. (1988) Japanese Journal of Applied Physics 27: L269–L271, and Mitschke and Bäuerle (2000) J. Mater. Chem. 10: 1471–1507.